Bone infections Flashcards

1
Q

what are staph aureus infections treated with

A

flucloxacillin

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2
Q

what are staph epidermis infections treated with

A

vancomycin

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3
Q

what are gram negative infections treated with (2)

A

doxycycline, clindamycin

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4
Q

how does bone infection present (5)

A
rubor (red) 
calor (hot) 
dolor (painful) 
tumour (swelling) 
function laesa (loss of function)
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5
Q

what investigations are most important for bone infections (2)

A

CRP

culture - for infecting organism

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6
Q

what are the 2 general treatments for a bone infection

A

antibiotics - when organism is diagnosed, 6 weeks minimum

surgery (debridement) - if theres pus, let it out!

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7
Q

what is acute osteomyelitis

A

inflammation of the bone and medullary cavity

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8
Q

where does acute osteomyelitis usually occur

A

long bones (eg legs)

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9
Q

what are the different aetiologies of acute osteomyelitis (6)

A
post surgery infection 
immunocompromised (children, elderly) 
open fractures 
vascular insufficiency eg diabetes 
haematogeneous spread
prosthetic joints
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10
Q

which infecting organism is most likely to cause acute osteomyelitis in an open fracture

A

staph aureus

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11
Q

how does acute osteomyelitis present in an open fracture

A

poor wound healing (non union)

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12
Q

what antibiotic is most likely to be used to treat an open fracture with acute osteomyelitis

A

flucloxacillin

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13
Q

which microorganism is most likely the infecting organism in acute osteomyelitis associated with vascular insufficiency (eg diabetes)

A

polymicrobial (staph aureus + something else)

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14
Q

how does acute osteomyelitis occur in someone with vascular insufficiency

A

through an ulcer = broken skin that doesnt heal = easily infected

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15
Q

what are the risk factors for haematogeneous spread of infection causing acute osteomyelitis (5)

A

immunocompromised

prepubertal children
elderly
PWID (people who inject drugs) 
central lines 
dialysis
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16
Q

what is the most likely causative organism of acute osteomyelitis caused by haematogenous spread of infection

A

staph aureus

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17
Q

is acute osteomyelitis caused by haematogenous spread of infection contagious or not

A

yes it is contagious

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18
Q

what is the complication of acute osteomyelitis caused by haematogenous spread of infection in;
adults?

children?

A

adults - SAPHO (synovitis acne pustulosis hyperostosis osteitis)

children - CRMO (chronic recurrent multifocal osteomyelitis)

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19
Q

what type of acute osteomyelitis can TB cause

A

vertebral osteomyelitis

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20
Q

what may patients present with if they have TB associated vertebral osteomyelitis

A

fever

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21
Q

what test needs to be done if someone is diagnosed with TB

A

HIV

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22
Q

what are the most common infecting organisms in acute osteomyelitis associated with prosthetic joints (2)

A

staph aureus

staph epidermis

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23
Q

what differs from the treatment of prosthetic joint acute osteomyelitis and the other types of acute osteomyelitis?

A

surgery to remove the joint is required, not debridement (though it may also be needed if bad)

24
Q

which immune complex is involved in trying to remove the infection in osteomyelitis

A

leukocytes

25
Q

what is the function of leukocytes in osteomyelitis

A

they cause bone lysis = pus can enter bone vessels = blocks them

blocked bone vessels = repair cant happen

= necrosis

26
Q

what word is used to describe bone after it has under gone necrosis in osteomyelitis, when there is new bone formation around the infected bone

A

involucrum bone

27
Q

what is the gold standard investigation for any type of acute osteomyelitis

A

biopsy

28
Q

what happens when acute osteomyelitis isn’t treated

A

it becomes chronic osteomyelitis

29
Q

what are the causes of chronic osteomyelitis (4)

A

untreated acute osteomyelitis
TB
diabetics
IVDU

30
Q

where does chronic osteomyelitis usually present (2)

A

the spine or pelvis

31
Q

what additional things will be in the presentation of someone with chronic osteomyelitis rather than just acute osteomyelitis (3)

A

anaemia
fatigue
malaise

32
Q

what is the treatment for chronic osteomyelitis

what treatment will probably be ineffective for osteomyelitis

A

likely amputation

antibiotics probably wont work

33
Q

what is septic arthritis

A

inflammation of a joint caused by infection

34
Q

what part of the joint is damaged in septic arthritis

A

articular cartilage

35
Q

what is the aetiology of septic arthritis (4)

A
inoculation from penetrating object 
metaphyseal spread (from bone to bone) 
intra-articular surgery (eg joint replacement) 
haematogenous spread (by blood, eg from endocarditis, trauma etc)
36
Q

if multiple joints are affected by septic arthritic, what should you suspect the cause is

A

infective endocarditis and haematogenous spread of the infection

37
Q

what is the most likely infecting organism that causes septic arthritis

A

staph aureus

38
Q

what is the most likely infecting organism that causes septic arthritis in kids

A

haem influenza (if they dont have the flu jab)

39
Q

what is the most likely infecting organism that causes septic arthritis associated with a prosthetic joint

A

coag negative staph

40
Q

what is the most likely infecting organism that causes septic arthritis in a young sexually active adult

A

neisseria gonorrhoea

41
Q

how does septic arthritis present

A
mono arthritic pain 
hot, red, swollen
v painful joint 
febrile (fever) 
tachycardia
42
Q

if someone presents with monoarthritic pain, what is at the top of your differentials

A

septic arthritis - it must be ruled out!

43
Q

apart form septic arthritis, what are the other differential of monoarthritic pain (3)

A

gout
enteropathic arthritis
reactive arthritis

44
Q

what is the first line investigation for septic arthritis

A

fluid aspirate of joint

45
Q

what is the first line investigation for any monoarthritic pain

why

A

fluid aspiration of joint

to exclude septic arthritis

46
Q

what is the treatment of septic arthritis (2)

A

antibiotics - flucloxacillin first then depending on organism
surgery - to remove pus and replace joint

47
Q

what symptoms and signs differentiate septic arthritis from gout

A

febrile (fever)
tachycardia
increased WCC

48
Q

what soft tissue infection feels like bubble wrap

A

necrotising fasciitis

49
Q

how do you prevent replacement joints getting infected

A

24 hours of antibiotics after surgery

50
Q

how does an infected arthroplasty present

A

fever
pus oozing from wound
pain around joint replacement

51
Q

what is a complication of untreated infected arthroplasty

A

chronic osteomyelitis

52
Q

how is an infected arthroplasty treated

A

surgery to remove pus

53
Q

what is pyomyositis

note not a bone infection lol

A

infection of skeletal muscle from haematogenous spread

54
Q

how does tetanus infection affect someone, ie pathophysiology

(note not a bone infection lol)

A

neurotoxins attack the CNS

55
Q

how does a tetanus infection present

when is it worst

(note not a bone infection lol)

A

muscle spasm/paralysis

worse in sunlight

56
Q

what does a tetanus infection look like on histology

note not a bone infection lol

A

a drumstick shape with a spore head

57
Q

how is a tetanus infection treated

note not a bone infection lol

A

surgical debridement
antibiotics
vaccine prophylaxis